Is this the only change in v3.0.2? I have customized my v3.0.0 and don't really want to deal with doing it again with a new version unless there is a calculation change. Thank! (and...did I miss anything importatn in v3.0.1?)

You can downlowad v3.0.2 and look at the Version Information tab to see the revision remarks for what was done at each revision.

That said, here's the info from that tab for those revisions (nothing substantial; although -TH- might beg to differ about that re: the donation button! ):

v3.0.1 9/2/2011 Added note: "When measuring actual mash pH with a meter, keep in mind that it can take up to 15 minutes for mash pH to stabilize." Also added "buy me a beer" link.

. . . . I noticed that I had put a 2x multiplier in my calculation on the spreadsheet for its affect on RA/mash pH. For the life of me I can't remember why I put that in there and I don't see anything in my notes. I think I am going to take this out for the next minor revision . . .

Still working on it but from my recent research I think the multiplier brings it closer to experimental data. Therefore I will probably leave it as is in my next version but maybe allow the user to adjust the multiplier if necessary based on their own results. You should be good using the current version.

That has something to do with the buffer the lactic sees. Understanding the apparent mash buffering capacity is something where I see a lot of variation in my data. When using bicarbonate alkalinity I tend to see a buffer capacity around 60 mEq/(kg*pH) while the use of an acid, like lactic shows a mash buffer of only ~30 mEq/(kg*pH). Some of this may be from the fact that the pH over mEq/kg relation ship is not linear and some of it comes from the fact that water alkalinity is also a buffer. And there might be other factors.

Since I saw lots of inconsistencies with that I ran lots of experiments in this area before I went on my "brewing science hiatus" almost 2 years ago. I was looking at this data just recently and will have to dig into this some more with renewed interest due to the new mash chemistry calculator that I wrote.

[QUOTE=Kaiser;4848307]When using bicarbonate alkalinity I tend to see a buffer capacity around 60 mEq/(kg*pH) while the use of an acid, like lactic shows a mash buffer of only ~30 mEq/(kg*pH).

I'm not following that at all but whenever I see a factor of two and carbonate/bicarbonate mentioned I suspect that definitions may be involved or the fact that carbonate absorbs 2 protons on the path to carbonic may have been overlooked.

I once bought an alkalinity test kit that returned a value twice the actual akalinity. A little investigation reveled that the manufacturer considered alkalinity to be 100 time the number of mEq/L required to hit the end pH. When I reported this to the source, Cole Parmer, they were kind enough to write back saying they had indeed checked with the manufacturer and that's correct - 100 time mEq. Saepe in errore, numquam in dubio.

I'm not following that at all but whenever I see a factor of two and carbonate/bicarbonate mentioned I suspect that definitions may be involved or the fact that carbonate absorbs 2 protons on the path to carbonic may have been overlooked.

I checked that and that's not what was going on. The apparent factor of two is interesting, though.

Not until recently I have been able to account for the buffer behavior of carbonic more accurately but that only accounts for some of the discrepancies I'm seeing.

Hi all,
Just got my water report, but it lists the Sodium results as "PENDING". Not sure what to do... Is there a typical (close enough) sodium number that I can plug into the EZ water calculator? Should I ignore and leave at zero? Here are the rest of my numbers:

Some of this may be from the fact that the pH over mEq/kg relation ship is not linear and some of it comes from the fact that water alkalinity is also a buffer. And there might be other factors.

I find that the pH vs meq/kg is VERY linear in the typical mash pH range. In that pH range, a large part of the water alkalinity has been exhausted. So it shouldn't be a factor. I suppose Kai was speaking about a wider range of pH.

The rule of thumb is high buffering within 1 unit of a pK. Assuming that a lot of the buffering comes from phosphate (a fair assumption since there is so much of it in malt) you are safely away from the closest pK's (which is exactly why 5.2 doesn't work) but of course there are dozens of other acids in malt.

I can't tell whether the titration curves are flat or not. I've measured some that are and some that aren't but that's because I've never measured one correctly - a process I must undertake when I have some time. It is going to be a very time consuming process - perhaps not so bad when I actually get rolling.

Now if bicarbonate is involved the first pK is 6.38. At any pH above 5.38 there will be appreciable buffering from bicarbonate - the higher you go the more there will be until you hit 6.38 at which point it starts to roll off again.

The graph below shows the buffering capacity in mEq/mmol - pH (1 mmol of carbo comes from 100 mg of lime or 84 mg of sodium bicarbonate) on the left axis and the number of mEq of mL of 23 Be' HCl (concentrated) which would have to be added to a liter of water with 100 mg of lime in it to reach the pH on the bottom axis. It's pretty plain from either of these curves that the buffering is substantial in the rule of thumb region and that the titration curve (the red one) is reasonably linear in that region. When outside, however, it is highly non linear.